Toll supervisory operator&#39;s telephone circuit



4 Sheet s-Sheet l R. B. BUCHANAN Nov. Z5, 1952 Filed Dec. 29, 1948 BBM.

4/NI/ENTO? BVR. B. BUCHANAN ATTORNEY Nov. 25, 1952 R. B. BUCHANAN TOLLSUFERVISORY OPERATORS TELEPHONE CIRCUIT Filed Dec. 29. 194e 4sheets-sheet 2 Nov. 25, 1952 l R. BQBUCHANAN TOLL. SUPERVISORY OPERATORSTELEPHONE CIRCUIT Filed Dec. 29, 1948 4 Sheets-Sheet 3 )NVENTOR En@ B.BUCHANAN W. CWM,

A T TORNEV Nov. 25, 1952 R. B. BUCHANAN TOLL SUPERVISORY OPERATORSTELEPHONE CIRCUIT Filed Deo. 29. 194e 4 Sheets-Sheet 4 /N VEA/TOR BV?.B. BUCHANAN A7' TORNEY Patented Nov. 25, 1952 TOLL SUPERVISORY OPERATORSTELEPHONE CIRCUIT Russell B. Buchanan, Lynbrook, N. Y., assgnor to BellTelephone Laboratories, Incorporated, New York, N. Y., a 'corporation ofNew York Application December 29, 1948, Serial No. 67,867 4 claims. (C1.179-27) This invention relates to semiautomatic tele- .phone systems andparticularly to such systems -in which dial systems A and B operatorpositions are provided at a toll switchboard.

I Objects of the invention arethe improvement ofsupervisory operatorcircuits at dial systems B switchboards to .render the supervisorcircuit accessible in common to dial systems subscribers .and to dialsystems' A and B operators.

'- According to this invention, a supervisory operators circuit isarranged to be accessible .alternately over each of two lines incomingfrom the switches of a cross bar dial ofce and to'be -accessible fromdial systems A and B operator positions'of a toll switchboard,preference being prising A and B operator positions, a supervisory.operator circuit and telephone set, and a distant toll board arrangedto route calls to the dial .system B operator positions.

The equipment in the cross bar oice repre- .sented in Fig. 1 is similarto that disclosed in- Patents 2,089,921 and 2,235,803 granted August-10, 1937, andMarch 18, 1941, respectively, to 1W. W..Carpenter. YL2 areshown, the line LI being shown as a call- Two subscriber lines LI anding line and the line L2 as a called line; and

.two lines I and 20 are shown for extending calls -Vto the dial system Bswitchboard supervisors circuit shown in Figs. 2 and 3. The dial systemvB operator position, keyset, sender, link and in- -coming Vtrunkcircuits shown schematically in Fig. 4 are similar to those disclosed inPatents 2,259,100 granted `October 14, 1941, to J.F. Dahl -.and Patent2,259,101 granted October 14, 1941, v to R. C. Davis, J. B. Newsom andW. B. Strickler.

vThe dial systems A operator positions andthe distant toll boardpositions of Fig. 4 may be simi- -lar'to those disclosed in Patent2,276,515 granted March 17, 1942, to T. D. Robb and Patent l.1,675,956granted July 3, 1928 to L. F. Porter. i The supervisors circuitdisclosed in detail in Figs. 2, 3I and 4 comprises incoming conductorsSII;- I2, I3. and,l4 of line. I0 andassociated call 2 lamps I5 andrelays SA, SAI, SA2, RA, LA, AA and CA; incoming conductors 2|, 22, 23and 24 of line 20 and associated call lamps 25 and relays SB, SBI, RB,LB; incoming conductors 'II, 'I2 and 'I3 from DSA positions of a tollboardand an associated relay SL; a call key at each DSB operatorposition and an associated relay SC and call lamp for use in calling asupervisor; a supervisors telephone circuit 60 jackended at each DSBposition, a plug-ended telephone set 50 for connection at any DSBposition with the telephone circuit 60, and relays AN and SR, which areoperated whenever the telephone set is plugged in at any position; aholding key B5 at each DSB position and an associated relay H forholding an incoming call after the telephone set is disconnected at aDSB position; and control relays LU, RT, TI and T. The supervisorstelephone set includes a receiver 5I, transmitter 52, a push-to-talk key53 and plugs 54 which cooperate with jacks 55 and 56 to connect thetelephone set for use. Talking battery is supplied to transmitter 52through the windings of retard coil y51 4and speech currents generatedinthe transmitter are transmitted through the windings of repeating coil58 and conductors 5I and 62 to a calling lineor operator. Speechcurrents incoming over conductors 6I and 62 actuatethe receiver 5I, thevolume being limited by thermistor 59.

Assume first that a DSA operator of the toll board calls the DSBsupervisor by inserting the plug of a cord CDI in the outgoing jack 10to which conductors 1I, 'I2 and 'I3 are connected; whereby battery isconnected through the sleeve conductors of the plug and jack 'I0 andconductor 'I3 to energize both windings of relay SL and operate thisrelay. With the talking key (not shown) of cord CDI operated, battery inthe position circuit is connected to conductors 'Il and I2 and fromconductor 'II through a back contactof relay LU to the upper windingY ofrelay RT; butrrelay RT is marginal and does not operate until theringing key (not shown) With relay RT operated, a circuit is closed forenergizing the operating room calling signal 45. When the call isanswered by the connection of a supervisors telephone set 55 totelephone circuit 60 at one of the DSB positions, the connection ofground to Yconductor 63 operatively energizes the windingfof relay AN.The operation of relay AN opens the circuit for energizing the operatingroom calling signal, closes a circuit for operating relay SR, and closesa circuit for operatively energizing the upper winding of relay LU.Relay AN also disconnectsground from the lower, low resistancegwindingof relay SL and connects battery through' resistor`33 ,to this Windingof relay SL thereby toy extinguish the supervisory lamp 'I5 of cord CDI.The operation of relay LU closes a locking circuit through its lowerwinding under the control of relays SL and H, opens the circuit forenergizing lamp 3U, disconnects the upper winding of relay RT H 'plug ofcord CDI from jack 15, relays SL and 4LU release in succession; and whenthe supervisory operator disconnects her telephone set i! `from positionjacks 55 'and'58frelays'AN and SR u release in succession.

Assume next that an operator at 'a' distant toll board calls the numberassigned to lines III and 2U and that the call is completed b y'a DSB'operator in' the manner described in thev above-mentioned patentsthrough trunk |50, incoming trunk circuit IGI, and primary and secondaryswitches of incoming link and line link frames. Upon seizure of line I0under control 'or the terminating marker; ground is connected tolconductor I4 thereby operating relay SA of the supervisor circuit. Theoperation of relay SA closes circuits for operating relaysV SAI and RA;connects conductor `I4 to the line sleeve conductorA I3 to operate theline hold rmagnet of the primary switch on the line link frame; connectsthe winding of relay SA directly to conductor I4 independent of relayLA; andA bridges toll positions; and closes circuits for operatingrelays SA2, T and TI. The operation of relay SA2 closes a lockingcircuit independent'of relay SBI under the sole control of relay SAI.The operation of relay T closes a locking circuit under control ofrelays SAI and SR. The operation of r.

relay TI closes a locking circuit independentY of relay SB under thecontrol of relays vSAI'and SR. When a supervisors telephone set 55 isconnected to position jacks 55 and 56 to answer the call, the connectionof ground to conductor l63 operates relay AN. The operation ofrelayAN'closes the circuit for operating relay SR; closes an' additionalcircuit path from battery through resistor 33 to the lower winding ofrelay SL; opens the circuit forv energizing thebperating room callingsignal 4D; and connects ground at the lowermost back contact of relay Hto conductor 32 to hold relays T and TI operated after relay SRoperates. The operation of relay SR completes a circuit including frontcontacts of relays T, TI and AN for operating relay The operation ofrelay LA opens the connection between'condenserl` I5 and-resistor Il;

bridges resistor Il across conductors II and I2 to effect the operationof a ringing trip relay (not shown) of the incoming trunk circuit IUI'inv usual manner to terminate the transmission of ringing current overthese conductors of line I;"and connects the winding of relay CA inparallel with resistor I1, whereby relay CA is operated. The operationof relay CA causes the release of relay RA, but relay RA is slow inreleasing to insure'operation of the ringing trip relay. After ringinghas been tripped, relay CA is held operated in series with the batteryfeed relay (not shown) ofincoming trunkicircuit IIlI.

The release of relayA RA* extinguishesrdivision all of the relays inthesupervisor circuit-release except relays AN and SR. Whenthefsupe'rvisors telephone set 5i) is disconnected from-position jacks55l and 55, relays' AN' andn SR release in succession.

yAssume next that a call from a toll operatoris routed through the crossbar switchesto Yline 2D. In this event relay SB is operated vupon`connection of ground to conductor 24 under control AVof the terminatingmarker. The-operation of relay SB closes circuits for operating relaysSBI'fand RB; connects conductor 24 to the'line sleeve 'conductor 23 tooperate the line hold magnety of=the primary switch on the'line linkframe; 'connects the winding of relay SB directly to vconductor 24independent of relayk LB; and VbridgesV condenser 25 and resistor 2l inseries acrossl conductors' 2| and 22 to satisfy the line continuitytest' which is made by the terminatingmarker. V'Ihe'opr'eration of relayRB lights the green 'call signal division lampsY 25 and the red`callfsignal lamps 36; and the operation of relay SBI closes'a'circuitfor'energizing the 'operating `roomcalling signal 4i). The operation ofrelay YSBI connects battery through resistor 33 to the lower winding ofrelay SLto mark the supervisory circuitbu'sy at outgoing trunk jacks 'I0at the tollboard DSA and toll positions; and closesV acircuit'for'operating relay T, but does not close'a circuit'ifroperating relay TI. The operationofrelay T closes a locking circuit forthis relay funder control of relays SBI and SR. `Wheni`af`super visorstelephone set'50 is connected Yto position jacks 55 and 55 to answerthe'call,v the connection of ground to conductor 53 operates' relay AN.The operation of relay AN closes thev circuit for operating relay SR;closes anadditi'on'alpath between battery through resistor'33to the'lwerwinding of relay SL; opens the circuit for energizing the operatingroom" callng'signal 4|); and

connects ground at the lowermost back contact of relay H to conductor 32to hold relay T operated after relay SR operates. The operation of relaySR completes a circuit including front contacts of relays T and AN and aback contact of relay TI for operating relay LB. Theoperation of relayLB opens the connection between condenser 26 and resistor 21; bridgesresistor 21 across conductors 2| and 22 to effect the operati'on of Atheringing trip relay (not shown) of trunk circuit IOI in usual manner toterminate the transmission or ringing current over these conductors ofline 20; and connects the winding of relay CB in parallel with resistor21, whereby relay-CB is operated. The operation of relay CB causesftherelease of relay RB, but relay RB is slow in releasing to insureoperation of the ringing trip relay. After ringing has been tripped,relay CB is held operated in series with the batte'ry feed relayv (notshown) of the incoming trunk-circuit IUI. tinguishes division lamps 25and 30; and closes a-circuit for operating relay AB. Relay AB closes alocking circuit which is under control of relay SB, and completes atalking connection between line conductors 2| and 22, through frontcontacts of relays SB and AB, back contacts of relay TI, front contactsof relay T, and conductors 6I and 62 to the telephone circuit 60 andanswering supervisors telephone set 50. The operation of relay ABprevents the reoperation of relay RB in case the supervisor disconnectsbefore the calling toll operator disconnects. When the calling operatordisconnects, all of the relays in the supervisor circuit release exceptrelays AN and SR. When the supervisors telephone set I] is disconnectedfrom position jacks 55 and 5B, relays AN and SR release in succession.

When it is necessary for a supervisor to hold an incoming connectionwhile answering another connection, one of the hold keys 65 in thedivision is operated, thereby connecting ground to conductor 66 tooperate relay H. When the telephone set 50 is disconnected from thedivision jacks 55 and 56, relays AN and SR release. If the call beingheld is a call incoming over line 20, the operation of relay H closes acircuit for holding relay T operated. If the call being held is acall-incoming over line I0, the operation of relay H closes circuits forholding both of relays T and TI operated. If the call being held is oneincoming from a DSA operator, the operation of relay H prevents theoperation of relay T in case a call comes in over either one of linesIll and 20 while relay H is operated;vboth the operating and lockingcircuits of relay LU are opened and relay LU releases; relay H maintainsthe connection of battery through resistor 33 to the lower winding ofrelay SL so as to continue the deenergiza-- tion'of the supervisory lamp15 in the cord circuit at the toll position. When the telephone set 50is reconnected to jacks 55 and 56, relays AN, SR and LU reoperate; and,when the hold key is restored to normal, relay H releases.

' If on a call from a DSA operator position, the calling operatordisconnects before the supervisory disconnects, relay SL releases butrelays AN and SR remain operated. With relay AN operated, the connectionof battery through resistor 33, lower winding of relay SL and conductor13 to the sleeve conductors of jacks is maintained as a busy indicationto any operator who may attempt to call the supervisor at this time. Ifon'a call from a DSA operator position, the calling.ioperatoridisconneots lwhile the holding The release of relay RB exkey65 is operated, relays-.AN and SR release `but relay H maintains theconnection of battery through resistor 33, lower winding of relay SL andconductor 13 to the sleeve conductors of jacks 10 as a busy indication.

If, on a call incoming over trunk |00 from a distant toll board to lineIc, the calling toll operator disconnects while a hold key 65 isoperated. the cross bar switches are released causing'the release ofrelaysSA, SAI, SA2, AA, and CA but relays T, TI and LA remain operatedunder the control of relay H. With relay SA released and relay LAoperated, ground is connected to conductor I4 toA mark the line IB busy.When the hold key 65 is restored to normal after the telephone set 5I)has been reconnected to jacks 55 and 55, relays'AN and SR are operatedand relay H releases. t release of relays TI and LA; but relay Tis heldoperated under control of -relay AN until the supervisor againdisconnects telephone set 50 from jacks 55- and 56. The release of relayLA disconnects the busy ground potential fromV conductor I4.

If, on a call incoming over trunk IIJU from a distant toll operator toline 20, the calling toll operator disconnects while the supervisorstelephoneA set is connected to jacks 55 and 56 or while a hold key 65 isoperated, the cross bar switches are released causing the release ofrelays SB, SB I, AB and CB; but relays T and LB are heldY oper-- atedunder control of relays AN and SR or under the control of relay H as thecase may be. With relay SB released and relay LB operated, ground isconnected to conductor 24 to mark line 2U busy. When the telephone set56 is disconnected from jacks 55 and 55 and key 65 is restored tonormal, relays AN, SR and H are released and relays T and LB release.The release of relay LB disconnects busy ground potential from conductor24.'

When nearly simultaneous calls are received on lines Ill and 2G, thesupervisors circuit operates to extend the calls to an answeringsupervisor in the order in which they are received. When a call from atoll board DSA operator is initiated `1 at a time when no calls overlines I6 and 20 are awaiting answer and calls come in over either orboth of lines Ill and 20 before the supervisorv connects telephone set55 to jacks 55 and 56, the call from the toll operator will be answeredrst; and, after this call has been answered, thev calls from lines I 0and 25 will be answered in the order` received. No calls should bereceived from' and this action is independent of whether the' callingoperator disconnects at the time the supervisor disconnects.

Assume that a rst call is received over line I0 and that immediatelythereafter a call is received over line 2li. In this case relays SA,SAI, SA2, RA, T and T I operate responsive to the call over line I0; andrelays SB, SBI and RB operate responsive to the call over line 20. Whena supervisors telephone set 5D is connected to jacks 55 and 56, relaysAN, SR and LA operate 'as hereinbefore described; and relay LB will be'pre-- vented from operating .due Jto..thenperation..of

The release of relay H causes thel relay TI..` With relays AN, SR andLAoperated*I 1 relaysCA, RA and AA function as hereinbefore describedandline conductors lll andY II are connected through conductors 6I and 62to the telephone circuit Bt. At this time,relays SA, SAI, SA2, AA, CA,LA, T, TI, AN, SR, SB, SB-I and RB are operated and relay RAhasreleased. At the end` of the conversationover line Iii, thesupervisors telephone set i! isv disconnected from, and then reconnectedto, jacks 55 and 55; where,i

byrelaysAN and SR are released and then reoperated. If, at this time,the calling operator has not disconnected, relays SA, SAI and SA2 remainoperated andthe release of relay, AN causes the release of relay TIdueto the fact that relay SRA is slow in releasing and ground isidisconnected from conductor 32 during the release time of relay SR; andthe locking circuit of relay-T is openedduring the releasetime of relaySR, .so that relay T releases. causes fthe releaseoi relay LA and therelease cf relay SR reconnectsv ground to conductor 32. When relays ANvand SR reoperate, relay T reoperates but the operating circuit of relayTl is held open due to the operation of both of relays SB and SA2.

Since lines lil and 29 are assigned the same number and constitute aline group similar to a private branch exchange group, calls waiting onboth lines le and 2B with the first of the two waitngcalls received online can occur only when a preceding call over line II) is answered andthen released and a new call received over line I before the call online '26 is answered. Under this condition, relays SB, SBI and RB areoperated upon seizure of line 2E! and relays SA, SAI and RA arereoperated uponreseizure of line I5; but relay SA2 cannot reoperatebecause its operating circuit is opened by the operation of relay SBI.RelayV T remains operated when the preceding call from line Il) isreleased; but relay TI releases when relay AN releases and cannotreoperate since relay SA2 ,is not operated. When relay SR reoperates,relay LB operates. After the conversation over line 20 is completed, thesupervisor again disconnects and reconnects the telephone set to jacksand When relay AN releases and until slow-to-release relay SR alsoreleases, a circuit is closed for operating relay TI, this circuitincluding the upper front contact of relay SBi, vback contact of relaySAZ, front contacts of relays SAI and SR, inner upper back contact ofrelay AN to ground at a back contact of relay H. When relay SR releases,ground is reconnected to conductor 32 to lock relay TI. Relay T is heldoperated since relay SAI is operated; and when relays AN and SRreoperate, relay T locks and relay LA operates followed by the operationof relay CA, the release of relay RA, and the operation of relay AA ashereinbefore described.

If a first call from a DSA operator is waiting together with a call overline I0, relay SL is operated and relays SA, SAI, SA2 and TI operate.Relay T cannot operate because its operating circuit is opened by theoperationY of relay SL; and therefore relay LA cannot operate.Y

Vlfhen a supervisor connects a telephoneset to jacks 55 and 55, relaysAN and SR operate and aV talking connectionv is completed between thecalling DSA operator and the supervisor. When the supervisordisconnects, relays AN and SR release. Ifthe DSA operator fails todisconnect, theY circuit for operating relay T is closed by the releaseof relay AN` while relay SR is releasing.

The release of relay AN d When` relay SR; releases, thelocking-circuit"of;A

When the supervisor. reconfrelay T is closed; nects thentelephone set tojacks. 55. and. 56, relays AN and SR reoperate and relay LA operates',and the call incoming yover line I0 is completed to the supervisor .ashereinbefore described.-`

If a DSBoperator wishes' to obtain the assistance of a supervisor', theoperation: of a .callkey Se connects ground `to conductor 9| to .effectoper-- ation of relay SC. Theoperation of. relay SC lights the whitecall lamp and the redflamp. 30,

and closes a circuit forY energizing'theoperating room calling signalim.` A supervisorl then'. goes to thev calling DSB; operator position.andlre` stores the key to normal, thereby releasing ,ref lay SC. toextinguish the call lamps and'deener.- gize the signal 40j.

An outogoing call may be initiated. by aDSB a supervisory operatorcircuit, lines from. said? automatic exchange to4 said operatorcircuit,a

toll spera-tor position at said toll switchboard, an outgoing truckjacl: at saidposition; a trunk linel from said jack to said operator;circuit, a` tele,- phone set, plug and jack meansV for connecting said.set to said operator circuitxto answer calls.

\ means in said circuitcomprising Aan individual relay for eachV saidvline for marking said trunkA jack busy, means in Lsaid automaticexchange fory seizing either one of said lines and rfor operatl-ng saidrelay or" the seized line and relay means in said circuit'controlled bysaid individual relays and rendered operative by connection of saidsupervisor set to said operator circuit for extending callsincorningover said lines from thauteinatic exchange to the telephone setin the arder in which the lines are seized.

2. In a telephone system, a supervisory operator circuit, automaticswitching means, first and second lines incoming to said circuitseizable by said switching means, an operator posiiton, a third lineincoming to said circuit seizable at said position, a callsignal'individual to each ofY said first and second lines, a .callsignal common to said lines, means individual to each of said first andsecond lines operable upon seizure of the associated line for energizingthe associated individual call signal andthe common call sig-- nal,means operable upon'seizure of said third line for energizing saidcommon call signal, a

telephone set and means for connecting saidsetV to said circuit toanswer an incoming call, and control means in said supervisoryoperatorcircuit comprising relay means for extending calls simultaneouslyawaiting answeron said rstand second lines to said telephoneset in theorder in which said lines are seized and comprising relay means forextending a call incoming over said third line to said supervisorycircuit only when -no other calls are awaiting answerv on said first andsecond lines or when the call awaiting answer on said third line isreceived before the calls awaiting answerY on said first and secondlines.

3. In a telephone system, a dial oiice, dial syse tems B operatorpositions, dial systems A operator positions, a supervisor circuitfor'said B op.

acid-54o erator positions, a telephone set, means f-or ccnnecting saidset to said circuit to answer calls incoming to said circuit, two linesincoming from said dial cnice to said circuit, a third line incomingfrom said A operator positions to said circuit, call signal meansindividual to each of said two lines, call signal means common to saidytwo lines and said third line, means operable responsive to seizure ofeither of said two lines for energizing the associated individual callsignal means and said common signal means, means operable upon seizureof said third line for energizing the corn- Inon call signal means, andcontrol means rendered operative by connection of said telephone set tosaid circuit for connecting said lines one at a time to said circuit toanswer an incoming call said control means comprising relay means forextending simultaneously waiting calls incoming over said two lines tosaid telephone set in t'he order they are received and comprising relaymeans for extending a call incoming over said third line to saidsupervisory circuit when no other calls are waiting or when the callawaiting answer on said third line is received before the calls waitingon said two lines.

4. In a telephone system, a supervisory operator circuit, automaticswitching means, rst and second lines incoming Ito said circuit seizableby `said switching means, an operator position, a third line incoming tosaid circuit seizable at said position, a call signal individual to eachof said rst and second lines, a call signal common to said lines, mean-sindividual to each of said first and second lines operable upon seizureof the associated line for energizing the associated ini@ dividual callsignal and the common call signal, means operable upon seizure of saidthird line for energizing said common call signal, a telephone set andmeans for connecting said set to said circuit to answer an incomingcall, rst and second control relays, means including front contacts ofbot-h o1" said relays for connecting said iirst line to said telephoneset, means including front contacts of said first relay and backcontacts of said second relay for connecting said second line to saidtelephone set, means including baci: contacts of said first relay forconnecting said third line to said telephone set, means for preventingthe operation of either of said relays after said third line is seized,means for operating said first relay when either said first or secondline is seized, means for operating said second relay only when saidiirst line is seized, and relay means effective when said iirst line isseized subsequent to seizure of said second line and both calls areawaiting answer to prevent the operation of said seco-nd relay.

RUSSELL B. BUCHANAN.

REFERENSES @FEED The following references are of record in the file ofthis patent:

UNTED STATES PATENTS Number Name Date 1,509,691 Richardson Sept. 23,1924 2,314,990 Kessler Mar. 30, 1943 2,352,107 Kessler June 20, 19442,427,000 Hovland Sept. 9, 1947 2,467,457 Balzer Apr. 19, 1949

